In the conventional abrasive type vertical milling machine grain is supplied to the milling chamber by screw conveyor and is milled in the milling chamber formed by abrasive roll assembly and cylindrical screen assembly. The screw conveyor is mounted on a main shaft extending vertically. The food grains hits the abrasive rolls in the milling chamber and milling action takes place. Milled food grains collected at bottom of milling chamber discharged through discharge disk. In the present machine all the abrasive roll assemblies are placed one over the other on the bottom plate and mounted on feed screw by long bolts.
One of the related arts discloses about a rice polishing machine of a vertical shaft and frictional type comprising a vertical tubular member having a perforated wall and a vertical shaft which is disposed in the tubular member and capable of being rotated therein with aid of a rotor. Thus, it teaches about having a shaft which may be confined to the bottom portion of the machine and may be rotated by means of pulley. Also, the perforation available on the vertical tubular member may enable the spiral rotor and the polishing rotor to be suspended therein.
One of the related arts disclosed about a vertical milling machine comprising milling parts and a main shaft wherein the rotation with alignment has been arrived at the bottom portion with aid of a rotation. Thus it teaches about having a rotation at the bottom of the shaft to maintain integrity of the milling machine and the shaft is present through out the milling machine and is being connected to all the rolls.
However, in all these existing arts, the abrasive roll assembly is rotated along the shaft present in it to which the abrasive roll assembly are coupled in appropriate position to enable it to rotate. In these types of milling machine, removing the abrasive roll assembly is difficult as they are coupled to the shaft through out. In addition removing the abrasive roll assembly disturbs the mechanical axial alignment and would cause lot to align the milling machine without which the milling machine cannot be made to function. Thus replacing and aligning the abrasive roll assembly along with the axis of the milling machine is too tedious and complex in these types of existing milling machines.
In the present machine it difficult to maintain alignment of axis of abrasive roll assemblies. Due to this it is difficult to maintain the constant gap between abrasive rolls and perforated screen in milling chamber.
Thus there arises a need for a milling apparatus wherein the abrasive roll assembly can be dismantled without disturbing the axial alignment and to couple it such that the axis of rotation can be achieved and thereby maintaining the integrity of the apparatus. Also, there arises a need to provide a rotation along with the locking of the abrasive roll assembly such that the rotation can be achieved with the intact coupling of the abrasive roll assembly along the axial centre of the milling apparatus.